Rust 项目从 cargo new 到编译运行

  $ cargo new hello
      Creating binary (application) `hello` package
  note: see more `Cargo.toml` keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
  目录树:
    .git/ (git 仓库)
    .gitignore  (8 B)
    Cargo.toml  (76 B)
    src/
      main.rs  (45 B)
  Cargo.toml:
    [package]
    name = "hello"
    version = "0.1.0"
    edition = "2024"
    
    [dependencies]
  src/main.rs:
    fn main() {
        println!("Hello, world!");
    }
  .gitignore: /target

  $ cargo build   (第 1 次,0.23 s)
     Compiling hello v0.1.0 (<实验目录>/proj/hello)
      Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.21s
  $ cargo build   (什么都没改,0.02 s)
      Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.00s
  $ cargo run
      Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.00s
       Running `<实验目录>/target/debug/hello`
  Hello, world!
  Cargo.lock(此刻出现):
    # This file is automatically @generated by Cargo.
    # It is not intended for manual editing.
    version = 4
    
    [[package]]
    name = "hello"
    version = "0.1.0"

  target/ 的结构(两层):
    debug/.cargo-artifact-lock  (0 B)
    debug/.cargo-build-lock  (0 B)
    debug/.cargo-lock  (0 B)
    debug/.fingerprint/
    debug/build/
    debug/deps/
    debug/examples/
    debug/hello  (438120 B)
    debug/hello.d  (279 B)
    debug/incremental/
  可执行文件 target/debug/hello:438120 字节(428 KiB)
  改一行字符串后 $ cargo build(0.14 s):
     Compiling hello v0.1.0 (<实验目录>/proj/hello)
      Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.11s

  $ cargo build --release(0.12 s)
     Compiling hello v0.1.0 (<实验目录>/proj/hello)
      Finished `release` profile [optimized] target(s) in 0.10s
  release 可执行文件:433792 字节;debug:438120 字节
  改源码后 $ cargo check(0.05 s):
      Checking hello v0.1.0 (<实验目录>/proj/hello)
      Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.03s
  改源码后 $ cargo build(0.11 s)
  $ target/release/hello 直接运行(不经过 cargo): Hello, rust! v2